Vehicle headlight



Jan. 13, 1931. w. H. WOOD VEHICLE HEADLIGHT Filed June 50, 1926 19: mod

. vent vii ilnii! Patented Jan. '13, 1931 WILLIAH H. WOOD, OI QUUTH EUCLID, OHIO I VEHICLE HEADLIGHT Application flled June so,

This invention relates to vehicle headlights and has for its object the provision of a new and'improved lens which shall enable the successful use of a two filament lamp '6 with a plain paraboloid reflector. The two desirable that the light pattern be substanl filament lamp which I particularly contemplate is one having two independently usable light sources located, one substantially above the other, and of substantially similar intensity and color, the purpose of the same being to enable the driver to elevate his li ht beam to the most advantageous anle w en driving on a deserted road or to epress the same when meeting other travelers.- -Uniformity of intensity and color is desirable in order to avoid the necessity of compelling the eyes to adjust themselves to a change; and for the same reason it is very tially the same both with the elevated beam and the depressed beam. Superposed upon these are the legal requirements of many States that no light, or only a very small amount of the same, be thrown above the horizontal plane, and that a rather substantial amount of light be thrown downwardly and laterally in order to illuminate the sides of the road.

The filaments of such lamps are generally made of concentrated shape, that is to say of very fine wire coiled into a small helix, each coil being generally bent to a V-shape with its'plane horizontal and its apex presented forwardl such is the nature of the device I have i1 ustrated in connection with this a plication, although I do not limit mysel thereto. When such a lamp bulb is employed in connection with a paraboloid reflector, one filament above and the other below the reflector axis the vertical displacement of each source from the axis causes a certain separation of the light rays, some parts of the reflected beam bein depressed and others elevated, and the shii t from one filament to theother causes an entire reversal in this pattern. The object of the present invention is the n'ovision of a simple and inexpensive type oi lens which in combination with a two filament lamp and a plain paraboloid reflector produces the light 1920. Serial No. 110,557.

pattern most desirable to drivers. A. further object of the invention is' the provision of a lens of this nature which when used with a two-filament lamp and a plain paraboloid reflector position of the ulb as to permit the omission of adjustin devices.' Another'object of the invention 18 the provision of a lens of such attern and design that its die work shall e conveniently and readily effected; while further objects and advantages of the invention will become apparent as the description roceeds.

In the rawings accompanying and forming a part of this application Fig. 1 is a vertical axial sectional view through a reflector,

ermits such variation in the 55 bulb, and lens embodying my improvements;

Fig. 2 is an elevation of the rear face of the ens shown in Fig. 1; Fig. 3 is a horizontal axial sectional view corresponding to the line 3-43 of Fig. 1; Fi 4 is a front elevation of the lens shown in Figs. 1, 2, and 3; Fig. 5 is a front elevation of a modified lens containing many of the features of my present inventionand Fig. 6 is a rear view of another modified form of lens.

In Fig. 1 I have shown a paraboloid reflector 1, since one of the main objects of my invention is to enable the use of such an unmodified reflector. Mounted on the axis of said reflector is the lamp bulb 2 having therein the two concentrated V filaments 3 and 4 located one above and the other below the focal point f of the reflector.

The essential characteristic of my improved lens is that the same is formed on one face with a plurality of prismatic ribs 5, 6, 7, 8, of varyin slope, the opposite ends of each rib being evel with each other, all of said prisms sloping in the same direction, the prisms of maximum slope being located at the upper and lower portions of the lens and decreasing as they approach the horizontal axis. The opposite face of the lens may be formed with upright corrugations or flutes 9, 10, whose spreading efiect is greatest near the vertical axis and least at the two sides, the flutes sometimes being wholly omitted near the lateral margins as shown at A-A in Fig. 5. It will be underfineinent decreases make because stood that each of these views is merely illustrative, and not attempted to be drawn to scale, because of the limitations of space. Thus, instead of merely two flutes 1010 of maximum curvature as illustrated in Fig. 3, a full sized lamp generally has a plurality of such flutes or corrugations at each side of the center line; and I have also exagger- Fig. 5.

The level prisms 5, 6, 7, 8, are omitted throughout the median portion of the lens, although the vertical flutes are continued therepast, at least throughout the portion nearest the vertical center. It is sometimes desirable, however, to modify very slightly this median portion of the lens for the purpose of increasing theintensity of the distance beam. It will be understood that, in general, this distance beam consists of the rays reflected at the two lateral portions of the reflector and transmitted through the regions A-A of the lens where the level prisms and the vertical flutes are either much reduced or wholly lacking; while the near-light and-the curb-light is produced by the downward deflection of prisms 5, 6, 7, 8, coupled with the lateral diffusion of the flutes 9. Excepting for the vertical flutes 9-9 the central horizontal zone A-A of the lens is substantially is sometimes desirable however, to form a limited region at the center prisms similar to those at 5, 6,7, 8, although the same should in no case extend to the lateral margins. The reason is that this rethe sensitivenes's of the device to variations in-the position of the filaments and helps to make a fixed focus lamp. The lens shown in Fig. 5"when employed in combination with a paraboloid reflector produces a very excellent two-filament combination if a focusing device be employed, while that the lenses illustrated 55 in igs fixed-focus lamp when used with a plain 1, 2, 3, 4, and 6 produce a successful paraboloid reflector. It is sufiicient for operative urposes if the prisms at the center of the Fig. 6, and such construction is very attractive in, appearance, but is difficult to of he necessity of an excess of hand labor for which reason I have devised a different form of rism so arranged that it can be made whol y by machine.

:' the upper fiat-and undeflecting -throughout as shown in Fig. 5, although it of the lens with ens be straight as shown at 13 in When used with a two-filamentlamp of the type herein shown, the dilferent portions of a paraboloid reflector exhibit the following phenomena Portions adjacent the heel of the reflector and behind the light .source reflect downwardly from the up er filament and upwardly from the lower lament; portions in front of the light source and on the vertical axis tend to reflect upwardly from the upper filament and downwardly from the lower filament, behaving in this manner exactly the opposite from the heel portion; and portions in front of .the light source but at the two side mar gins of the reflector reflect downwardly from the upper filament and upwardly from the lower filament in much the same way as the heel, and in quite the opposite manner from the upper and lower forward margins. The most difficult portion of the reflector to control is that portion lying in and near the vertical longitudinal plane the reflector axis since the reaction of the forward portion of this zone to vertical displacement of the light source is different from that of every other part of the re-' flector and becomes more pronounced with increasing distance from the parameter'at which point the beam exhibits a,minimum of sensitiveness. I locate in front of this portion of the reflector a series of prisms of varying inclination, this inclination being greatest at and lower margins and decreasing towards the axis of the lamp. The result of this is to depress the rays which would otherwise stray and cause-glare. It is undesirable, however, that these rays should be concentrated in a mere' streak alon the center of the road, for which reason show upright flutes-to spread and deflect the same to constitute a curb light. The rays reflected at the two sides of the reflector near the central horizontal plane suifer the least deflection when the current is shifted from one filament to the other and are hence employed for distant lighting; and for this reason the upright flutes, if used at all at this point, are made of comparatively small curvature so that the beam may not be spread too widely.

I consider the prisms 20 at the center of.

- the reflector as being of secondary importance. When used they depress '(and when curved also deflect laterally) those rays of 1i ht which emerge through the center of t elens. In case the lamp filaments are accurately ositioned inside the reflectorit is general y better that these central prisms be omitted and the light concentrated at a ever, if these filaments be not accurately po- It is for this reason that distance instead of being di- 1 verged and scattered downwardly; howwhich includes tion of the lens, and hence if the desiderat-um be the productionof a fixed focus lamp, the

use of these prisms obliterates these dazzling rays and increases the tolerance of the device.

I have shown my improved lens as located with the level prisms on the rear face and hence inside the reflector, and this is the preferred arrangement owing to the greater ease of keeping the same clean; however, so far as concerns the optical features, the device could equally well be used in reverse position. I have omitted any illustration of the particular means of supporting the reflector and lens and securing them together, since any suitable or convenient expedient may be employed. It will also be understood that my improved lens, or some modification thereof, may be used in combination with a warped or modified reflector, despite the fact that its main object is to dispense with the necessity of so doing; and it will also be understood that it can be used successfully with a single filament lamp, despite the fact that its main object is to facilitate the use of a double filament device.

Having thus described my invention what I claim is:

1. The combination with a paraboloid re fiector and an incandescent lamp having two independently usable concentrated filaments located respectively above and below the axis of said reflector in substantially the same vertical line with its focal point, of a lens having a plurality .of level prismatic ribs both above and below the center line of said lens, the bottom face of each rib being substantially perpendicular to the lane of the lens and the upper faces of all 0 said ribs all slanting in the same direction, the angle of such slant decreasing progressively from the upper and lower margins as they approach the center line of the lens.

2. The combination with a paraboloid reflector and an incandescent lamp having two independentlyusable concentrated filaments located respectively above and below the axis of said reflector in substantially the same vertical line with its focal point, of a lens having on one face a plurality of level prismatic ribs all slanted in the same vertical direction whose angle decreases progressively from the upper and lower margins towards the central horizontal plane, and having upright corrugations on the other face extending from'top to bottom of the light transmitting portion whose curvature is greatest near the central vertical axis and decreases toward the lateral margins.

3. The combination with a paraboloid reflector and an incandescent lamp having two 65 independently usable concentrated filaments located respectively above and below the axis of said reflector in the same vertical line with its focal point, of a lens having. a comparatively lane portion near each lateral margin, an upright flutes on one face adjacent to its upper and lower margins, combined with a plurality of level downwardly deflecting prisms on its opposite face both above and below its median horizontal portion, said prisms all slanted in the same direction and progressively decreasing in slope from the upper and lower margins of said lens.

4. A lens for the purpose described havin on one face flutes extending to the to an bottom margins of the light transmitting portion which decrease in curvature from the vertical axis towards the lateral margins and having on the opposite face parallel prisms all sloped in one direction and which progressively decrease in slope from the vertical margins towards the horizontal axis.

5. A headlight lens for use with an incandescent electrlc lamp havin two independently usable concentrated filaments located upon a vertical line which is perpendicw. lar to the lamp axis said lens characterized by being formed on one face with a plurality of level horizontal prismatic ribs,

allslanted in the same direction, the slant of said ribs being greatest at the top and bottom margins of the lens and decreasing progressively from such top and bottom margins toward the central horizontal zone,

and said horizontal prismatic ribs being omitted from at least a ortion of the cen- I tral horizontal zone of said lens.

6. A lens for the purpose described having at one side of its central zone a series of parallel ribs and on the opposite side of its central zone a second series of parallel ribs, all of said ribs sloping in the same direction and the slope of. the ribs increasing with increase of the distance from the lens center in each direction.

In testimony whereof I hereunto afix my signature.

WILLIAM H. WOOD.

DIS' LA M R 1,788,935- -William H. Wood, South Euclid, Ohio. VEHICLE HnAnLIGn'r. Patent I dated January 13, 1931. Disclaimer filed October 29, 1931, by the patentee Thereforedisclaims from the scope of claim 6 all lenses excepting those wherein the central zone contains one or more window portionsfor the transmission of the distance beam with less deflection of the transmitted light than any other equal area of the? lens, and wherein the graduated increase in the slope of the ribs continues substantially all the way to the upper and lower margins of the reflector, andwherein the lens is employed in combination with a parabollc reflector and a lamp-bulb having plural filaments located one at a level above the reflector axis and another .at a lower level than said first filament, said filaments being symmetrically arranged relative .to the vertical plane which includes said axis.

. [Ofieial Gazette December 1,'1931.]

DISCLAIMER 1,788,935.William H. Wood, South Euclid, Ohio. VEHICLE HEADLIGHT. Patent dated January 13, 1931. Disclaimer filed March 22, 1935, by the patentee.

Hereby enters this disclaimer to that part of the claim in said specification which is in the following Words, to wit: 7

5. A headlight lens for use with an incandescent electric lamp having two independently usable concentrated filaments located upon a vertical line which is perpendicular to the lamp axis, said lens characterized by being formed on one face with a plurality of level horizontal prismatic ribs, all slanted in the same direction, the slant of said ribs being greatest at the top and bottom margins of the lens and decreasing progressively from such top and bottom margins toward the central horizontal zone, and said horizontal prismatic ribs being omitted from at least a portion of the central horizontal zone of said lens.

6. A lens for the purpose described having at one side of its central zone a series of parallel ribs and on the opposite side of its central zone a second series of parallel ribs, all of said ribs sloping in the same direction and the slope of the ribs increasing with increase of the distance from the lens center in each direction.

[Ofiicial Gazette April 23, 1935.] 

